The present invention relates to a method and apparatus for measuring the quantity of particles and, more particularly, to a method and apparatus for measuring the quantity of particles deposited on a metal body to be coated with a powder, wherein a high electrostatic field is applied between the body forming one electrode and a second electrode mounted at a distance or spacing therefrom, and wherein a particle current is introduced into the field space.
Several types of power coating methods have been proposed which may be used, for example, for corrosion proofing of welded seams on metal cans for, for example, accommodating food and, it is extremely important that a layer thickness be produced which is not adversely affected by disturbing factors which may take on various forms.
In one proposed method, where the body to be coated usually functions as an electrode, with a second electrode being mounted at a spacing or distance therefrom with the space for the high electrostatic field being formed therebetween one such factor is that not only the desired body coating is applied but also an undesired coating of the opposite electrode occurring as a result of changes of both polarities occurring in the field defined between the first and second electrode. This particular proposal produces an increasingly severe incrustation and corresponding changes in the electrostatic field leading, in turn, to a decrease in the quantity of powder deposited per unit of time on the body to be coated.